Increasing the WordPress Memory Limit
This setting is advised when there's a memory allocation issue on your site or when you receive an error message such as:
"Allowed memory size of xxxxxx bytes exhausted".
1. Edit your wp-config.php file and increase PHP memory:
Note: WordPress memory can be different to the server – you need to set this regardless of server memory settings
http://codex.wordpress.org/Editing_wp-config.php#Increasing_memory_allocated_to_PHP
2. If you have access to your PHP.ini file, change the line in PHP.ini
If your line shows 32M try 64M:
3. If you don’t have access to PHP.ini try adding this to an .htaccess file:
php_value memory_limit 64M
4. If none of the above works, contact your hosting provider and ask them to increase the WordPress memory limit.